Switch part

[rajeevsri]

If PC1 ip address 10.0.0.20 and PC2 ip address 10.0.0.30 are connected to two different switches-1 interface valn 20 and switch-2 valn 30 and they are on the network but assigned to different VLANs, they cannot communicate directly without a router

[Martin L]

Yes, correct but there might be a trick to make so they do ping ok in that scenario; let me check... will reply soon

Regards, ML
**Please Rate All Helpful Responses **

[Reza Sharifi]

As long as both IPs are on the same network and the ports are configured as access ports, you can have one host in vlan 20 and the other one in vlan 30. 

HTH

[Joseph W. Doherty]

By "router" you also include L3 switch, correct?

If the VLANs are not bridged, yes you would need L3.  There are multiple ways to bridge the VLANs.

[Richard Burts]

I will add one item to the helpful response by Reza. He says that if both PCs are connected to access ports. I would add that if the switch to switch connection is also an access port. then the IPs will successfully communicate. If the switch to switch connection is a trunk then the IPs will not communicate.

I believe that this is what Joseph describes when he mentions bridging the VLANs.

[rajeevsri]

Yes, you may correct 

[Martin L]

So, besides having access link between 2 switches, there was another trick with Native vlan.  Native vlan id is different between 2 interconnecting switches; then PCs on the same subnet but in different vlans were OK. This seems to not work any longer in IOS 15.x. I am having problem re-creating the issue right now - spanning tree is blocking ports due to native vlan mismatch.

Regards, ML
**Please Rate All Helpful Responses **

[Rich R]

Assuming this wasn't intended to be a SPAM post (which it looks like it might have been because @rupeshah edited it):
@rajeevsri you've made a statement (of the obvious subject to the exceptions the others have listed above) but what was your actual question?

[rajeevsri]

I am able to ping from P1 to P2 destination.